Field of Disclosure
Embodiments described herein generally relate to formulating an empirical model for determining the inflow performance relationship of multilateral wells.
Description of the Related Art
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Multilateral wells are deployed widely by the oil and gas industries. In spite of their high cost of deployment, multilateral (or multi-branched) wells have been drilled in order to develop an effective technology that increases the amount of hydrocarbon recovery required to meet the ever-growing demand for global oil and gas. Accordingly, the productivity performance of such multilateral wells is important.
In the work conducted by Vogel in “Inflow Performance Relationships for Solution-Gas Drive Wells”, JPT 20 (1), 83-92, and incorporated herein by reference in its entirety, equations are developed that can be used for analyzing the Inflow Performance Relationship (IPR) for wells drilled in solution gas driven reservoirs. However, the model developed by Vogel is applicable only for vertical wells and is not suitable (due to complexity issues) for wells having fishbone (multi-branched) architecture. Further, generalized Vogel equations are commonly used to analyze the IPR for fishbone wells when these wells are producing below bubble point pressure. However, the generalized model developed by Vogel completely ignores the number of lateral branches (also referred to as rib-holes) and the effect of the rib-holes on the IPR of the wells.
Raghavan et al. in “Productivity of multiple drain-holes or fractured horizontal wells”, SPE Formation Evaluation 10 (1):11-16, 1993, and incorporated herein by reference in its entirety, developed a model based on the effective wellbore radius concept, wherein the fluid flow regime between the rib hole was assumed to be horizontally oriented. Larsen in “Productivity computations for multilateral, branched and other generalized and extended well concepts”, SPE 36754, presented at the SPE Annual Technical Conference & Exhibition held in Denver 6-9 Oct. in 1996, and incorporated herein by reference in its entirety, described a pseudo-radial skin computation procedure in order to estimate the productivity of multi-branched wells.
Retnanto et al. in “Performance of Multiple Horizontal Well Laterals in Low-to-Medium-Permeability reservoirs”, SPE Reservoir Engineering 11 (2): 73-77, 1996, and incorporated herein in its entirety, described a semi-analytical pseudo steady state well productivity formula for multilaterals wells by coupling a linear flow (1D) model and a radial flow (2D) model in the drainage area. Further, Salas et al. in “Multilateral Well Performance”, SPE 35711 presented at Western Regional Meeting held in Anchorage, Ak., 22-24, May 1996, and incorporated herein by reference in its entirety, described numerical simulators that can be utilized to determine analytically, the inflow performance relationship for several multilateral configurations of different skin factors. The work of Salas was further improved by Yildiz in “Multilateral Horizontal Well Productivity”, SPE 94223 presented at SPE Europe/EAGE Annual Conference held in Madrid, Spain, 13-16 June, and incorporated herein by reference in its entirety. Yildiz described a technique to model three-dimensional analytical solutions for multilateral/dual horizontal wells in anisotropic reservoirs.
Additionally, the work conducted by Retnanto et al. in “Inflow Performance Relationship of Horizontal and Multi-branched in a Solution Gas-Drive-Reservoir”, SPE 50659 presented at SPE European Petroleum Conference held in The Hague, Netherlands, 20-22 October, and incorporated herein by reference in its entirety, described a technique to compute IRP for horizontal and multi-branched wells taking into account the effect of bubble-point pressures. Furthermore, Guo et al. describe in “Well Productivity Hand Book”, Gulf Publishing Company, Houston, Tex. 226-230, which is incorporated herein by reference in its entirety, a model that combines several flow regimes such as vertical radial flow, reservoir radial flow and reservoir linear flow.
A drawback of the above stated works is that the respective models estimate the productivity of the oil wells without considering the effect of the number of rib-holes (i.e., lateral branches) of the fishbone wells. Accordingly, there is a requirement to develop an empirical model that estimates the IPR of fishbone wells produced from two-phase saturated reservoirs (i.e., when reservoir pressure is below bubble point pressure) by taking into account the number of rib-holes of the fishbone well.